Programmable de-fogger system for a light projector

ABSTRACT

A light projector for operation during a show that contains theatrical haze. The light projector may include a light source, a lens, a fan, and a housing having an inner chamber. The lens may have a first side and a second side. The first side of the lens may be contained within the inner chamber of the housing. The second side the lens may be outside of the inner chamber of the housing. The fan may be configured to be operated to generate air flow inside the inner chamber of the housing. A substantial portion of the air flow may be directed to impinge upon the first side of the lens to cause de-fogging of theatrical haze condensate on the first side of the lens.

CROSS REFERENCE TO RELATED APPLICATION(S)

The present application is a divisional of and claims the priority ofU.S. patent application Ser. No. 13/350,932, titled “PROGRAMMABLEDE-FOGGER SYSTEM FOR A LIGHT PROJECTOR”, filed on Jan. 16, 2012.

FIELD OF THE INVENTION

This invention relates to improved methods and apparatus concerninglight projectors used on theatrical stages.

BACKGROUND OF THE INVENTION

Light projectors are often used on theatrical stages to lightentertainers. Some light projectors make use of patterns or electroniclight valves to project images onto projection screens or stagesurfaces.

U.S. Pat. No. 7,048,383, to Belliveau discloses a filter system methodand states in its “Background of the Invention”: “During a theatricalpresentation the Image projection lighting devices are often operated inconjunction with theatrical fog generating devices. The theatrical fogor smoke generating devices are used to create an airborne haze that canbe used as a projection surface creating three dimensional imagery. Thefog generating devices create the airborne haze by propelling minuteparticles into the air which can remain suspended in the air for aconsiderable time. The minute particles are commonly created by the foggenerating devices by atomization of oils or glycols. The glycol ormineral oil particles (referred to herein as fog particles) can eachrange in size from between twenty microns to below 0.1 micron.

When lighting devices such as image projection lighting devices containcomplex optical and electronic components the fog particles may be drawnthough the cooling system and may condense on the various opticalcomponents diffusing the projected image or shortening the life of thecomponents.” (U.S. Pat. No. 7,048,383 to Belliveau, col. 2, line 30-col.2, line 49)

Filters systems like that disclosed in U.S. Pat. No. 7,048,383 toBelliveau amount to a considerable expense of a light projector whendesigning an economical light projector system. There is still a needhowever to prevent critical optical components from condensing with fogparticles when by design no adequate filter system is incorporated intothe product. Output lenses of image projection lighting devices, maytypically have an inner surface that is located in the internalenvironment to a lamp housing and an external surface that is exposed anexternal environment of the lamp housing. Because there can be atemperature differential between the inner surface and the outersurface, theatrical fog haze can typically form condensate on the innersurface or even the outer surface. When the condensation forms on thelens the output light can become defused by the light scatteringproperties of the condensate. The output lens can be a lens having anoptical power or a transparent output window.

More recent light projectors may comprise a light source of a solidstate LED light source that emits less infrared energy than halogen orarc light sources making the problem of controlling condensation bytheatrical haze even more difficult because the output lens absorbs lessinfrared energy from the light source and thus operates at a lowertemperature.

There is a need to find a method of reducing condensate on at least oneoptical component of a light projector without using a costly filtrationsystem.

SUMMARY OF THE INVENTION

One or more embodiments of the present invention provide a lightprojector for operation during a show that contains theatrical haze. Thelight projector may include a light source, a lens, a fan, and a housinghaving an inner chamber. The lens may have a first side and a secondside. The first side of the lens may be contained within the innerchamber of the housing. The second side of the lens may be outside ofthe inner chamber of the housing. The fan may be configured to beoperated to generate air flow inside the inner chamber of the housing.The fan may be configured to be operated to generate air flow inside theinner chamber of the housing. A substantial portion of the air flow maybe directed to impinge upon the first side of the lens to causede-fogging of theatrical haze condensate on the first side of the lens.

The light projector may be further comprised of an operator input panelin communication with the fan, and configured to allow an operator toselect any one of a plurality of de-fogging functions to be executed bythe fan. The plurality of de-fogging functions may include operating thefan to cause de-fogging only when the light projector is not being usedto project light. The plurality of de-fogging functions may includeoperating the fan when the light projector is projecting light.

The light projector may be further comprised of a communications port;and the communications port may be configured to receive de-foggercommands from an external control device. The communications port may bein communication with the fan to execute the de-fogger commands. A firstone of a plurality of de-fogging functions to be executed by the fan maybe configured to be selected by an operator of the external controldevice.

The external control device may be a lighting console. Thecommunications port may receive de-fogger commands compliant with theDMX protocol. The first one of the plurality of de-fogging functionsselected by the operator may operate the fan to cause de-fogging onlywhen the light projector is not being used to project light.

In at least one embodiment of the present invention a light projectorfor operation during a show that contains theatrical haze may beprovided. The light projector may include a light source, a lens, aresistive conductor, and a housing having an inner chamber. The lens mayhave a first side and a second side. The first side of the lens may becontained within an inner chamber of the housing. The second side of thelens may be outside of the inner chamber of the housing. The resistiveconductor may be positioned relative to the lens to cause de-fogging oftheatrical haze condensate on the lens. The resistive conductor may beapplied to the first side of the lens. The resistive conductor may be apower resistor.

In at least one embodiment of the present invention a light projectorfor operation during a show that contains theatrical haze is provided.The light projector may include a light source, a lens, an infraredlight source, and a housing having an inner chamber. The lens may have afirst side and a second side. The first side of the lens is containedwithin the inner chamber of the housing. The second side the lens may beoutside of the inner chamber of the housing. The infrared light sourcemay be positioned relative to the lens to project infrared light ontothe lens to cause de-fogging of theatrical haze condensate on the lens.The infrared light source may be project light to a perimeter of thelens to cause heating of the lens. The infrared light source may becomprised of at least one infrared light emitting diode.

At least one embodiment of the present invention may include a methodcomprising generating an air flow inside an inner chamber of a housingof a light projector, so that a substantial portion of the air flow isdirected to impinge upon a first side of a lens fixed to the housing tocause de-fogging of theatrical haze condensate on the first side of thelens. The method may be further comprised of selecting any one of aplurality of de-fogging functions via an operator input panel fixed tothe housing to cause de-fogging of theatrical haze condensate on thefirst side of the lens. The plurality of de-fogging functions mayinclude operating a fan to cause de-fogging only when the lightprojector is not being used to project light from the housing; and/oroperating the fan when the light projector is projecting light from thehousing.

The method may be further comprised of receiving de-fogger commands at acommunications port fixed to the light projector from an externalcontrol device; and causing the received de-fogger commands to beexecuted by a fan to generate the air flow.

The external control device may be a lighting console. Thecommunications port may receive de-fogger commands compliant with theDMX protocol. The first one of a plurality of de-fogging functionsselected by the operator may operate the fan to cause de-fogging onlywhen the light projector is not being used to project light.

In another embodiment of the present invention, a method is provided,comprising fixing a light source, and a lens to a housing, and fixing aresistive conductor to the housing, in a position with respect to thelens so that the resistive conductor causes de-fogging of theatricalhaze condensate on the lens. The resistive conductor may be applied tothe first side of the lens. The resistive conductor may be a powerresistor. The method may further include fixing a light source, and alens to a housing, and fixing an infrared light source, so that theinfrared light source projects infrared light onto the lens to causede-fogging of theatrical haze condensate on the lens. The infrared lightsource may project light to a perimeter of the lens to cause heating ofthe lens. The infrared light source may be comprised of at least oneinfrared light emitting diode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of an apparatus in accordance with an embodimentof the present invention;

FIG. 2A shows a front view of an output lens for use with an apparatusof FIG. 3A;

FIG. 2B shows a side view of another embodiment of an output lens foruse with an apparatus of FIG. 3B;

FIG. 2C shows a front view of a further embodiment of an output lens foruse with the apparatus of FIG. 4;

FIG. 3A shows a diagram of an apparatus of another embodiment of thepresent invention;

FIG. 3B shows a diagram of an apparatus of another embodiment of thepresent invention; and

FIG. 4 shows a diagram of an apparatus of a further embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a diagram of an apparatus 100 in accordance with anembodiment of the present invention.

The apparatus 100 includes a lamp housing 101, a communications port112, a power input connection 118, a processor circuit board 120,communications port 208, a processor 210, a light source control 220, acomputer or electronic memory 212, a device output control 214, aconnection point 230, a connection point 232, a device output control216, a connection point 240, a connection point 242, a power supply 225,an external operator control panel 260, a user input key 264, a userinput key 266, display device 262, a cooling fan 310, a heat sink 322, alight source 328, a light condensing lens 334, an output lens 350, anair exiting vent 312, and a de-fogger fan 355. An inner chamber 101 b islocated within the housing 101, and is shown in FIGS. 1, 3A, 3B, and 4.An external environment 101 a, outside of the inner chamber 101 b andhousing of the housing 101 is also shown in FIGS. 1, 3A, 3B, and 4.

The lamp housing 101 may be an external lamp housing. The communicationsport 112 may be an external communications port connection that may be aDMX compatible connection. The power input connection 118 may be a powerline connection. The processor circuit board may be a microprocessorcircuit board. The processor 210 may be a microprocessor.

The connection point 230 may connect to connection point 232 (forsimplification of wiring to light source cooling fan 310). Theconnection point 240 may connect to connection point 242 (forsimplification of wiring to de-fogger fan 355).

An air direction arrow 308 shows the direction for input air passingthrough light source cooling fan 310. An air direction arrow 312 showsthe direction for light source cooling air passing through fan 310 tocool light source heat sink 322 attached to light source 328.

The light source LED 328 may be a solid state light source LED (lightemitting diode). The heat sink 322 may be a heat sink for the lightsource LED 328.

A light path direction arrow 330 shows a light path direction to thelight condensing lens 334. A light path direction arrow 340 shows alight path direction for light exiting condensing lens 334.

The output lens 350 has a side 350 a that is in the internal environment(i.e. within the housing 101) and a side 350 b that is in the externalenvironment (i.e. outside of the housing 101). A light path directionarrow 360 shows the direction of projected light exiting the lightprojector 100. An air direction arrow 314 shows the direction of exitinglight source cooling air. An air direction arrow 316 shows the directionof air flow due to de-fogger fan 355.

The output lens 350 has a first surface 350 a that is located in theinternal environment to the lamp housing 101 and an external surface 350b that is exposed an external environment of the lamp housing 101.Because there can be a temperature differential between the firstsurface 350 a and the second surface 350 b theatrical fog haze cantypically form condensate on the surface 350 a but can also form on side350 b. When the condensation forms on the lens 350 the output light asshown by arrow 360 can become defused by the light scattering propertiesof the condensate. The output lens 350 can be a lens having an opticalpower or a transparent output window.

The use of a solid state LED light source for light source 328 thatemits less infrared energy than halogen or arc light sources makes theproblem of controlling condensation by theatrical haze even moredifficult because the output lens 350 absorbs less infrared energy fromthe light source and thus operates at a lower temperature.

FIG. 2A shows a front view of the output lens 350 along with a resistiveconductor 370 for use with an apparatus 100 a of FIG. 3A.

FIG. 2B shows a side view of the output lens 350 along with a resistiveconductor 380 for use with the apparatus 100 b if FIG. 3B.

FIG. 2C shows a front view of the output lens 350 along with infraredlight sources 386 and 388 for use with an apparatus 100 c of FIG. 4.

FIG. 3A shows a diagram of an apparatus 100 a of another embodiment ofthe present invention. The apparatus 100 a is identical to the apparatus100 except as will be described. The apparatus 100 a includes connectionpoint 244 and a resistive conductor 370 which are not present inapparatus 100. Apparatus 100 of FIG. 1 includes connection point 242 anddefogger fan 355, which are not present in apparatus 100 a. The diagramof apparatus 100 in FIG. 1 also shows direction arrow 316 for air flowdue to defogger fan 355, which is not present in FIG. 3A.

FIG. 3B shows a diagram of an apparatus 100 b of another embodiment ofthe present invention. The apparatus 100 b is identical to the apparatus100 except as will be described. The apparatus 100 b includes connectionpoint 244 and a resistive conductor 380 which are not present inapparatus 100. Apparatus 100 of FIG. 1 includes connection point 242 anddefogger fan 355, which are not present in apparatus 100 b. The diagramof apparatus 100 in FIG. 1 also shows direction arrow 316 for air flowdue to defogger fan 355, which is not present in FIG. 3B.

FIG. 2A and FIG. 3A, together, show an alternate method of de-foggingshowing a resistive conductor 370 that dissipates heat. The resistiveconductor 370 can be applied to the lens 350 on either side 350 a or onside 350 b, shown in FIG. 1, or on both sides 350 a and 350 b. Theresistive conductor 370 may be applied to either surface or side 350 aor 350 b of the output lens 350 or may be molded into the opticalmaterial that the lens 350 is comprised of.

FIG. 2B and FIG. 3B, together, show an alternate method of de-foggingshowing a resistive conductor 380 that dissipates heat. The resistiveconductor 380 (which may be a power resistor package) may be placedaround the lens 350 on the perimeter surface 350 c in order to aid inthe heating of the lens 350.

In any case a resistive conductor, such as 370 or 380 is used to applyheat to the lens 350 in order to raise the temperature of the lens 350and cause theatrical fog particles to evaporate from the lens 350 at amore rapid rate reducing or eliminating condensate.

The resistive conductor 370 of FIG. 2A or the resisitive conductor 380of FIG. 2B may be variably controlled by the device output control 216(shown in FIGS. 3A and 3B), (through connection points 244 and 240 shownfor simplification of the drawing of FIGS. 3A and 3B). The resistiveconductor 370 of FIG. 2A or the resistive conductor 380 of FIG. 2B maybe variably controlled to be off, on or dissipating variable wattageunder the control of the device output control 216.

In this case as shown in FIGS. 3A and 3B the device output control 216and output connection 240 (for simplification) would be connected toconnection point 244 to supply power to the resistive conductor 370 (or380) to raise the temperature of the surfaces (such as surfaces or sides350 a, 350 b, and 350 c (shown in FIG. 1) of the lens 350. Raising thetemperature of the lens 350 causes the theatrical fog particles toevaporate at an increased rate helping to prevent condensate fromforming on the surfaces or sides 350 a, 350 b, and 350 c of the lens350.

FIG. 4 shows a diagram of an apparatus 100 c of another embodiment ofthe present invention. The apparatus 100 c is identical to the apparatus100 except as will be described. The apparatus 100 c includes infraredlight sources 386 and 388, which are not present in apparatus 100 ofFIG. 1. FIG. 4 shows light direction arrow 386 a to show direction oflight from infrared light source 386, and light direction arrow 388 a toshow direction of light from infrared light source 388. Light directionarrows 386 a and 388 a are also not present in FIG. 1.

FIG. 2C shows another variation of an embodiment of the presentinvention where lens 350 on any of the plurality of sides or surfaces350 a, 350 b or 350 c has infrared energy directed towards the lens 350in order to raise the operating temperature or the lens 350. Shown are aplurality of infrared light sources 386 and 388 with correspondinginfrared light output arrows 386 a and 388 a. The infrared light isdirected towards the lens 350 at any surface or side 350 a, 350 b or theperimeter surface 350 c to raise the temperature of the lens and causethe theatrical fog particles to evaporate from the lens 350 at a morerapid rate reducing or eliminating condensate.

In this case as shown in FIG. 4 the device output control 216 and outputconnection 240 (for simplification) would be connected to connectionpoint 242 to supply power to the infrared light sources 386 and 388 thatemit infrared light upon the lens 350 as shown by the correspondinginfrared light direction arrows 386 a and 388 a to raise the temperatureof the surface 350 a, 350 b or 350 c of the lens 350. Raising thetemperature of the surface 350 a, 350 b or 350 c causes the theatricalfog particles to evaporate at an increased rate helping to preventcondensate from forming on the surface or side 350 a of lens 350.

The preferred method of de-fogging is by the use of the de-fogging fan,such as fan 355, shown in FIG. 1, as it is the most economical to employto the light projector. The fan 355 may be a tube axial fan, a blowerfan or any other type of air moving device.

For FIG. 1 the de-fogger fan 355 is shown positioned to blow de-foggingair in the direction shown by arrow 316 onto the surface or side 350 aof the output lens 350. The de-fogging air helps to keep the surface 350a dry and free from condensate. It is an important to note however thatthere can be a side effect to blowing de-fogging air directly on thelens 350 to accomplish de-fogging. Since the light projector orapparatus 100 does not have a filter system and incoming cooling airpulled in by the cooling fan 310 shown by the arrow 308 is not filtered,the air within the housing 101 is subject to containing dust and debris(along with the theatrical haze particles) found in the externaloperating environment of the light projector or apparatus 100. Blowingde-fogging air onto lens 350 that also contains debris can result in thelens becoming dirty so it is best to limit the de-fogging air to aminimum depending on the amount of theatrical haze used in the show.

In operation of the light projector 100, the exposure to theatrical hazeparticles may vary depending on the application. For some shows therequirement of theatrical haze for the show may be quite high and thusmore de-fogging air to the lens surface 350 a may be required. Morede-fogging air can be accomplished by either duration (how long thede-fogger fan 355 is enabled to output air or by varying the CFM (cubicfeet per minute) of the de-fogger fan 355).

Because there are varying conditions of theatrical fog during the showuse of the light projector it is desirable for the operator of the lightprojector, such as apparatus 100, to choose varying de-fogging functionsfor de-fogging by the de-fogging fan 355, such as:

(1) Condition One, User Settable Function One:

For shows that utilize lower amounts of theatrical haze it is typicallyonly necessary to use the de-fogging fan 355 when the light projector100 is not being operated or projecting light in direction 360 from lens350. In this case the de-fogger fan 355 can be switched on to de-fog thelens 350 when the light projector 100 is not being used. When the lightprojector 100 is not being used it is highly likely that the theatricalhaze is not being generated in the show venue since in all likelihoodthe haze generator will also be off. The action of the de-fogger fan 355is optimum (the air produced by the de-fogger fan 355 in the directionof arrow 316 is dryer since it contains lower amounts of haze particles)when there is low or no theatrical haze particles in the environmentwithin the housing 101 because the venue is not continuously generatinghaze.

(2) Condition Two, User Settable Function Two:

For shows that utilize higher amounts of theatrical haze than conditionone, the de-fogger fan 355 can operate during the use of the lightprojector 100, i.e. while light is projected in direction 360 from lens350. In the case of condition two, the amount of air produced to de-fogthe lens 350 when the light projector 100 is operated or projectinglight is set to a first level amount of air flow. This can beaccomplished by cycling the fan 355 off and on (interval control) or byreducing the CFM (cubic feet per minute) (voltage control) of the fan355 during continuous operation. Fan control using interval control orby voltage control is known in the art but in any case the result is afirst level of air flow that is reduced compared to the action ofcondition three, user settable function three to be described below. Thereduced air flow of function two settable by an operator of the lightprojector 100 allows for successful de-fogging of the lens 350 withoutover applying air flow to the lens 350 that could result in debriscollecting on the lens 350 at an increased rate.

(3) Condition Three, User Settable Function Three:

For shows that utilize maximum amounts of theatrical haze the operatorof the light projector can choose function 3 where the de-fogger fan 355operates to maximum apply air (in the direction of arrow 316) to thelens surface 350 a of the output lens 350 while the light projector isbeing operated or projecting light.

(4) Condition Four, User Settable Function Four:

For shows that utilize no or very low amounts theatrical haze it is notnecessary to operate the de-fogger fan 355 either when the lightprojector 100 is operated or the light projector 100 is off (not inuse). This can save the lens 350 from having any debris from blowingonto the lens 350 by the defogger fan 355 during a de-fogging functionsuch as function one, two or three. For function four the de-fogger fan355 is disabled from operating either during the time the lightprojector 100 is operated or if the light projector 100 is not operatedor projecting light.

FIGS. 2A-B show alternative methods of de-fogging the lens 350.

FIG. 1 shows light projector 100 with housing 101. A circuit system orcircuit board 120 is shown that contains the electronics that enablesthe light source 328 and contains device output controls 214 and 216.Device output control 214 controls the cooling fan 310 for the lightsource 328 (through connection points 230 and 232 for simplification ofthe drawing). The light source cooling fan 310 brings in external airfrom the outside environment in the direction of arrow 308 and appliesair in the direction of arrow 312 to a heat sink 322. The light source328 may be a solid state light source and the light source 328 may beconnected to the heat sink 322 in order to dissipate unwanted heatgenerated by the light source 328. The light source 328 may be adifferent type of light source such as a plasma, halogen or electricarc.

The light output by the light source 322 as shown by arrow 330 iscollected by condensing lens 334. The condensing lens 334 outputs thecollected light in the direction of arrow 340 to be collected by outputlens 350. The lens 350 outputs the collected light as shown by arrow 360to be projected upon a performer, screen or stage surface during a show.The output lens 350 has a plurality of sides or surfaces. Lightcollection side 350 a of lens 350 is located within the housing 101.Light output side 350 b of lens 350 is located to the outside of housing101 and is exposed to the outside environment. Lens 350 also shows side350 c which is the perimeter of the lens 350. Cooling air generated bythe light source cooling fan 310 in the direction of 312 passes over theheat sink 322 and finds exit at the exiting vent 312 to the externalenvironment in the direction of arrow 314.

A communications connector 112 may be compatible with the DMX theatricalprotocol as known in the art. The communications connector 112 routesthe external communications (which may also be compatible with the DMX“Digital Multiplex” theatrical protocol) to communications port 208. Thecommunications port 208 provides external control system commands to theprocessor 210. The processor 210 acts in conjunction with the memory 212under operating system instructions, such as computer software orcomputer programmed instructions, that have been stored in the memory212. The memory 212 may be a computer memory or electronic memory suchas RAM (random access memory) or ROM (read only memory) or other type ofmemory. The processor 210 acting upon operating system instructions cansend control commands to the light source control 220 to enable thelight source 328 upon external commands received by the communicationsport 208.

The processor 210 upon receiving external communications from thecommunications port 208 and acting upon operating system instructionscan send control commands to the device output controls 214 and 216.Device output control 214 can enable and control the light projectorcooling fan 310 (through connection points 230 and 232 shown for wiringsimplification). Device output control 216 can enable and vary theoutput of the de-fogger fan 355 (through connection points 240 and 242shown for wiring simplification).

External connector 118 is a power connector that may be a line cord andis connected to a power source. Connector 118 routes power to the systempower supply 225. The system power supply 225 supplies the power to thecircuit 120, the light source 328, the light source cooling fan 310 andthe defogging fan 355.

An external operator control panel 260 that can be mounted to thehousing 101 of light projector 100 has input keys 264 and 266. Theoperator control panel 260 has a display device for feedback to theoperator so that different choices of the plurality of de-foggingfunctions as selected by the input keys 264 and 266 can be selected bythe operator.

The external operator control panel 260 transmits input commands to theprocessor 210 that can act with operating instructions or computersoftware stored in the memory 212 to select one of a plurality ofde-fogging functions by operator input action to the input keys 264 and266 and displays the selected function to the operator by means of thedisplay device 262.

The communications port 208 may also receive external commands via theexternal communications connector 112 and the external commands cancontain de-fogging function commands. External commands received by thecommunications port 208 may be compatible with known DMX theatricalprotocol. The processor 210 can receive the external commands from thecommunications port 208 and act with operating instructions stored inthe memory 212 to select one of a plurality of de-fogging functions asdesired by input action by an operator to a known external show controldevice or lighting console (not shown). De-fogging functions for thelighting projector 100 may be selected by either the external operatorcontrol panel 260 that may be fixed to the housing 101 or by externalcommands received by the communications port 208 as inputted by anoperator of a known external show control device or lighting console.

Although the invention has been described by reference to particularillustrative embodiments thereof, many changes and modifications of theinvention may become apparent to those skilled in the art withoutdeparting from the spirit and scope of the invention. It is thereforeintended to include within this patent all such changes andmodifications as may reasonably and properly be included within thescope of the present invention's contribution to the art.

I claim:
 1. A light projector for operation during a show that containstheatrical haze, the light projector comprising: a light source; a lens;a fan; a housing having an inner chamber; and wherein the lens has afirst side and a second side; wherein the first side of the lens iscontained within the inner chamber of the housing; wherein the secondside the lens is outside of the inner chamber of the housing; whereinthe fan is configured to be operated to generate air flow inside theinner chamber of the housing; and wherein the fan is configured to beoperated to generate air flow inside the inner chamber of the housing;and wherein a substantial portion of the air flow is directed to impingeupon the first side of the lens to cause de-fogging of theatrical hazecondensate on the first side of the lens.
 2. The light projector ofclaim 1 further comprising an operator input panel in communication withthe fan, and configured to allow an operator to select any one of aplurality of de-fogging functions to be executed by the fan.
 3. Thelight projector of claim 2 wherein the plurality of de-fogging functionsinclude operating the fan to cause de-fogging only when the lightprojector is not being used to project light.
 4. The light projector ofclaim 2 wherein the plurality of de-fogging functions include operatingthe fan when the light projector is projecting light.
 5. The lightprojector of claim 3 wherein the plurality of de-fogging functionsinclude operating the fan when the light projector is projecting light.6. The light projector of claim 1 further comprising a communicationsport; and wherein the communications port is configured to receivede-fogger commands from an external control device; wherein thecommunications port is in communication with the fan to execute thede-fogger commands; and wherein a first one of a plurality of de-foggingfunctions to be executed by the fan is configured to be selected by anoperator of the external control device.
 7. The light projector of claim6 wherein the external control device is a lighting console.
 8. Thelight projector of claim 6 wherein the communications port receivesde-fogger commands compliant with the DMX protocol.
 9. The lightprojector of claim 6 wherein the first one of a plurality of de-foggingfunctions selected by the operator operates the fan to cause de-foggingonly when the light projector is not being used to project light.
 10. Alight projector for operation during a show that contains theatricalhaze, the light projector comprising a light source; a lens; a resistiveconductor; and a housing having an inner chamber; and wherein the lenshas a first side and a second side; where the first side of the lens iscontained within the inner chamber of the housing; wherein the secondside of the lens is outside of the inner chamber of the housing; andwherein the resistive conductor is positioned relative to the lens tocause de-fogging of theatrical haze condensate on the lens.
 11. Thelight projector of claim 10 wherein the resistive conductor is appliedto the first side of the lens.
 12. The light projector of claim 10wherein the resistive conductor is a power resistor.
 13. The lightprojector of claim 10 wherein the resistive conductor is configured tobe responsive to a plurality of de-fogging functions from a controldevice; and wherein the plurality of de-fogging functions includeoperating the resistive conductor to cause de-fogging only when thelight projector is not being used to project light.
 14. The lightprojector of claim 10 wherein the resistive conductor is configured tobe responsive to a plurality of de-fogging functions from a controldevice; and wherein the plurality of de-fogging functions includeoperating the resistive conductor to cause de-fogging when the lightprojector is projecting light.
 15. The light projector of claim 10further comprising a communications port; and wherein the communicationsport is configured to receive de-fogger commands from an externalcontrol device; wherein the communications port is in communication withthe resistive conductor to execute the de-fogger commands; and wherein afirst one of a plurality of de-fogging functions to be executed by theresistive conductor is configured to be selected by an operator of theexternal control device.
 16. The light projector of claim 15 wherein theexternal control device is a lighting console.
 17. A light projector foroperation during a show that contains theatrical haze, the lightprojector comprising: a light source; a lens; an infrared light source;a housing having an inner chamber; and wherein the lens has a first sideand a second side; where the first side of the lens is contained withinthe inner chamber of the housing; wherein the second side the lens isoutside of the inner chamber of the housing; wherein the infrared lightsource is positioned relative to the lens to project infrared light ontothe lens to cause de-fogging of theatrical haze condensate on the lens.18. The light projector of claim 17 wherein the infrared light sourceprojects light to a perimeter of the lens to cause heating of the lens.19. The light projector of claim 17 wherein the infrared light source iscomprised of at least one infrared light emitting diode.
 20. The lightprojector of claim 18 wherein the light source projects light to thefirst side of the lens, to a central region of the lens, andsubstantially perpendicular to the first side of the lens.